Stretch resistant sail web

ABSTRACT

A sail web is provided having a plurality of layers of material, each layer of material being stretch resistant along at least one axis and having threads aligned along the axis which are substantially parallel to each other, the layers being overlapped so that the stretch-resistant axes thereof cross with one another. Preferably the layers are bonded together.

United States Patent [191 Andersen 1 1 STRETCH RESISTANT SAIL WEB [75]inventor: Jeff H. Andersen, Marblehead,

Mass,

22 Filed: July 13,1973 2| Appl. No.1 378,951

[52] U.S. Cl. 114/103 [5 1] Int. Cl B63h 9/04 [58] Field of Search114/103; 161/55, 57-60, l61/DIG. 4; 244/142, 145

[56] References Cited UNITED STATES PATENTS 1,341,396 5/1920 Swantees161/55 2,546,230 3/1951 Modiglianim. 161/58 2,552,124 5/1951 Tallman161/59 [451 Sept. 9, 1975 2,705,692 4/1955 Petterson 1. 161/55 2,803,5768/1957 Donaldson 4 .1 161/59 3,274,968 /1966 Hayes et al. 114/1033,642,561 2/1972 Grobner .1 161/57 FOREIGN PATENTS OR APPLICATIONS892,528 3/1962 United Kingdom .1 114/103 Primary ExaminerTrygve M. BlixAssistant ExuminerStuart M. Goldstein [5 7 1 ABSTRACT 12 Claims, 3Drawing Figures STRETCH RESISTANT SAIL WEB FIELD OF THE INVENTION Thisinvention relates to sail web for sails, particularly multi-layerstretch resistant sail web.

THE PRIOR ART For many years, until the late '40s, sails were madetraditionally from various types of canvas cloth. This cloth, the bestavailable at the time, suffered performance-wise from wrinkling, beingwetted, particularly with salt water and stretched and distorted fromexposure to wind and weather, to different shapes or sets in differentwind velocities and soon lost its designed shape which lessened itseffectiveness. A further serious drawback with canvas was that the clothwas not durable on exposure to wind and weather, showing signs of wearand rot after only two seasons in many cases.

An improved sail cloth became available in the late 40s and early 50swhich soon relegated canvas sails to practical obsolescence. These newsail cloths were of synthetic fibers such as woven nylon and wovendacron sailcloth. Sails of this new material proved to be very durable,stand up well to salt water, are impervious to rot, less effected bywrinkling, less subject to shape distortion with use and in generalprovided and still provide a tougher, durable sail than heretofore. Thesynthetic sails, particularly those of dacron, which is morestretch-resistant that nylon, continue in widespread use today as therecognized best available sail cloth.

However, even these synthetic sail cloths have their disadvantages,which are recognized by sail designers and sail makers and are factoredinto the construction of a sail, e.g. a main or jib. For example, intraditional construction of a sail using 5 ounce dacron material, shapedistortion occurs under wind pressure in three directions along the biasof the weave, as indicated, for example in FIG. 1. Thus the sailstretches at angles to the direction of the fibers constituting theweave so that the sail takes different shapes in different winds,heavier winds, of course, stretching and distorting the sail shape morethan light winds. If a sail is designed and cut to take a proper shapein heavy air or winds, it will take a distorted shape in light winds andviceversa. Accordingly, the sail made of the above materials must bedesigned and cut to take a compromise shape that is neither optimum forlight or heavy winds but is somewhere in between according to the bestguess of the sail designer.

In addition, the synthetic sails of the prior art are subject to thewear of time and typically have a useful racing life, particularly inthe jib, of about two years, after which the sail distorts out of itsdesigned shape, the sail cloth wears or loses bonding agent, renderingthe sail cloth thinner in places and with the passing of time the sailsbecome more and more out of shape. In addition, the sails are relativelyexpensive to construct; the fabric must be woven, panels must be cut,the panels must then be sewed together and since this cloth is subjectto fraying, a hemming must take place at each edge of the sail. Inaddition, the comers of the sails are reinforced with board" and theluff of the sail reinforced with a tape or rope woven therein, whichhave difierent stretch rates than the remainder of the sail cloth andunder stress, tearing of the sail cloth can occur at the boundary ofsuch sail cloth with these non-stretch or low-stretch zones. When tearsoccur a time-consuming and expensive sewing operation must be conductedto sew a patch onto the sail, care being taken to align the fibers ofthe patch with remainder of the sail, which can result in a lumpy airfoil for a sail. In addition, these woven sails are not assmooth-surfaced as is desirable with the resultant drag problemsattendant thereto.

Because of the above drawbacks, there is a need and market for a durablestretch-resistant sail which obviates the above problems.

There has now been discovered a stretch-resistant sail web which isvirtually distortion free, which takes virtually the same shape in lightair as in heavy air, sub ject to trim, which permits the design andcutting of a sail which is a more efficient air foil for various windconditions; which sail is faster, cheaper and easier to manufacture andto repair; which web does not fray and does not require hemming, whichis less subject to tear, due to lack of stretch, non-stretch boundariesin the sail.

SUMMARY DESCRIPTION These and other novel features will become apparentfrom the following detailed specification and drawings in which:

FIG. I is an elevation schematic view of traditionally woven syntheticsail cloth and FIG. 2 is an elevation schematic view of a multilayeredsail web embodying the present invention.

FIG. 2A is an enlarged fragmentary view of the sail web, taken from 2Aof FIG. 2.

Referring now to the drawings, conventional dacron woven sail 10 haspanels 12, l4, l6, l8 and 20 sewn together at respectively seams 13, 15,I7 and 19, to define the sail as shown in FIG. 1. A panel, for example,panel 12, is constructed of a weave of dacron threads 22 and 24 in agrid pattern, which threads are stiffened by a bonding agent (notshown). The threads 24 and 22 are subject to stretch in diagonaldirections a, b and c as shown by the arrows in P16. 1. Such stretchwill change the shape of the sail in accordance with respective windvelocities into not readily predictable shapes. To protect the weavefrom fraying at the edges, the sail is turned under and hemmed at theedges and has hem: 26, 28 and 30, which terminate respectively at thereinforced comers of the sail, i.e. non-stretch headboards 32, 24 and36, as shown in FIG. 1.

In cutting this sail of FIG. I, the sail maker must take into accountthe type of synthetic fabric being used and its stretch characteristicson the diagonal which varies with the thickness thereof, i.e. the weightthereof, hand cutting the respective panels by exercising his best guessas to what the material will do under wind pressures, by which acompromise factor is added, so that the sail will perform in heavy aswell as light airs and although many sail makers employ computers in thesail design process, the resulting sail is a product of guess work,experience and compromise.

The sail web embodying the present invention is constructed into sail 38which is formed by a plurality of webbed layers 40, 42 and 44 offiberglass as shown in FIGS. 2 and 2A. The webbed layers of sail 38 asshown in an enlarged fragmentary view, FIG. 2A, are of threesuperimposed layers of fiberglass, 40, 42 and 44, each layer being wovenin a grid pattern, with the threads of each layer, i.e. the non-stretchaxes of each layer being positioned at an angle with respect to the axesof the other two layers, such that each layer resists materialstretch ordistortion in different directions, as shown in FIG. 2A. In fact, thethree layer web as shown in FIGS. 2 and 2A resist stretch in sixdifferent directions, i.e. the directions along which the respectivethreads of each layer lie. As shown schematically in FIG. 2, each layer,40, 42 and 44 is postioned with one set of its threads parallel to anedge of the sail 38 such that stretch along the three sides of the sailis resisted by threads aligned parallel therewith, as shown in FIG. 2.The corners of sail 38 are reinforced respectively at the tack 50, theclew 46 and the head 48 by adding additional layers of fiberglassmaterial at these locations as shown in FIG. 2. All the fiberglasslayers are bonded together with bonding agent (not shown).

The sail web of the invention can be employed to construct a sail asshown in FIG. 2, resulting in a sail that has no appreciable stretchdistortion under wind pressure. The result is that an aerodynamicallymore efficient sail can be designed and manufactured to achieve an airfoil which will not change its shape after prolonged use. In fact, thesail of the present invention, including the sail camber, is adjustedfor different wind conditions by the sheeting tension applied to thesail, to give the sail the desired shape and to that extent the sail isself-adjusting.

The sail web of the present invention can be constructed from variousnon-stretch flexible web materials, such as fiberglass, graphite and thelike, which exhibit no significant stretch along the axis thereof.Preferred is fine mesh fiberglass material, preferably in the range of0.5I ounces to 4.0 to 7.0 ounces per square yard.

At least two layers of stretch-resistant material are employed in thesail web of the present invention, normally layers being placed acrosseach other such that their axes of stretch resistance cross at an anglewith one another. Each axis is defined by a plurality of threadssubstantially parallel to each other and parallel to the leach, luff,and the foot of a sail.

Although any number of layers of stretch resistant material can beemployed at the sail web of the invention, three crossed layers ispreferred to provide a satisfactory stretch resistant sail web, and whena sail is formed, an additional multiple of layers is preferably addedto the corners of the sail to build up or reinforce the strength of thesame.

Where three layers of stretch resistant material are employed, thematerials are preferably crossed so that one set of the threads of eachare respectively parallel to the leach, the luff and the foot of thesail to be formed.

The layers of stretch resistant material can be contaeted with a bondingagent or formed separately and then bonded together as a multi-layeredsail web. Preferably, however, as many layers as are desired areoverlaid, one atop the other, and then adhered together by bondingagent, the bonded materials being cured under heat and pressure ormerely heat or merely room temperature overnight.

If the stretch-resistant material, e.g. fiberglass is bonded in contactwith a glass or other smooth surface the resulting sail web surfaceadjacent to the glass has a highly smooth sheen thereto which providesan im proved air foil. Accordingly, if the sail web of the invention isbonded between two glass surfaces, a sail web results with two smoothsides. In another method, two sail webs which have been cured on a glasssurface can thereafter be bonded together at the respective rough sidesthereof, resulting in a multi-layered sail cloth having two sheen-smoothsides to provide an advantageous sail foil.

The multi layers of the sail web of the invention are bonded withvarious bonds suitable in the art, such as neoprene rubber, vinyladhesives, acrylic latex and the like. For fiberglass material,preferably acrylic latex is employed.

In addition to providing stretch-distortion resistant sails, the sailweb of the invention lends itself to fast, efficient low-cost sailassembly in contrast with present day methods of sewing sail clothpanels together. In place of cutting, positioning and sewing panelstogether and hemming the same, one, under the present invention, may layout on a suitable surface layers of stretch resistant material, e.g.fiberglass layers, one atop the other at different fiber directions, canmerely spray or brush the binder onto the layered material and quicklyform the sail subject to the curing thereof. No sewing is required andnon-skilled labor may be employed in the fabrication of sails accordingto the present invention. To reinforce the corners of the above sail,scraps of fiberglass, or rather stretch resistant material, may be addedto the comers prior to the binding step. Since the cured sail web is notfrayed, no hemming step is required.

The stretch resistant layers of material may be laid out in the form ofthe sail to be constructed, bonded and cured or such layers may be laid,bonded and cured and either panels may be cut therefrom to be bondedlater into a sail or the finished sail may be cut from such bondedlayers of the sail web.

Another improvement employed by the present invention is in repair ofsails. The sails of dacron, nylon and other materials when torn arerepaired by replacing an entire panel and stitching the same or byinstalling a patch and stitching around the edges of the patch which islaborious and provides an interruption of air flow of said sail. In therepair of the sail web of the present invention, the torn area canmerely be cut out of the web, multi-layered replacement materialinserted in the cutout portion and binding agent applied into themulti-layered replacement material and its surrounding sail web and uponcuring and setting of the bond, the repaired portion blends with theoriginal sail web in an uninterrupted air foil. Such repair is rapid,low cost and highly efiective.

Sail web of the present invention may be colored any desired color, i.e.by latex base paint or other suitable dye means.

To illustrate the low cost production of the sail web and sailsaccording to the present invention, present day daeron sails areproduced at manufacturer's costs at about cents per square foot, wheresails according to applicant's invention can be produced at 17 cents persquare foot.

What is claimed is:

l. A stretch-resistant sail web comprising a plurality of layers ofthreaded material, each layer of material being stretch-resistant alongat least one axis thereof and having threads aligned along said axis,said threads being substantially parallel to each other, said layersbeing overlayed such that the stretch-resistant axes of said layerscross at angles and which thread defining axes are aligned respectivelysubstantially parallel with the leach, luff and foot positions of asail.

2. The sail web of claim 1 wherein said layers are bonded together.

3. The sail web of claim I wherein said layers are of fiberglassmaterial bonded together.

4. The sail web of claim 1 wherein said layers are bonded together withacrylic latex.

5. The sail web of claim 1 having three layers of material withstretch-resistant axes aligned respectively substantially parallel withthe leach, luff and foot positions of a prospective sail.

6. The sail web of claim 1 having different number of said layers atvarious positions of said web.

7. The sail web of claim 1 having layers of threaded materials.

8. The sail web of claim 1 having bonded layers of woven material toform a fray resistant web.

9. The sail web of claim 1 having layers of .50 to 4.0 ounces per squareyard of fiberglass bonded together.

10. The sail web of claim 1 cut and bonded to form a stretch-resistantmulti-layer sail.

11. The multi-layer sail of claim 8 having additional layers of materialadded at the corners thereof to reinforce same.

12. The multi-layer sail of claim 8 having layers of tiberglass bondedtogether with adhesive.

1. A stretch-resistant sail web comprising a plurality of layers ofthreaded material, each layer of material being stretchresistant alongat least one axis thereof and having threads aligned along said axis,said threads being substantially parallel to each other, said layersbeing overlayed such that the stretch-resistant axes of said layerscross at angles and which thread defining axes are aligned respectivelysubstantially parallel with the leach, luff and foot positions of asail.
 2. The sail web of claim 1 wherein said layers are bondedtogether.
 3. The sail web of claim 1 wherein said layers are offiberglass material bonded together.
 4. The sail web of claim 1 whereinsaid layers are bonded together with acrylic latex.
 5. The sail web ofclaim 1 having three layers of material with stretch-resistant axesaligned respectively substantially parallel with the leach, luff andfoot positions of a prospective sail.
 6. The sail web of claim 1 havingdifferent number of said layers at various positions of said web.
 7. Thesail web of claim 1 having layers of threaded materials.
 8. The sail webof claim 1 having bonded layers of woven material to form a frayresistant web.
 9. The saIl web of claim 1 having layers of .50 to 4.0ounces per square yard of fiberglass bonded together.
 10. The sail webof claim 1 cut and bonded to form a stretch-resistant multi-layer sail.11. The multi-layer sail of claim 8 having additional layers of materialadded at the corners thereof to reinforce same.
 12. The multi-layer sailof claim 8 having layers of fiberglass bonded together with adhesive.